POLARIZATION CHARACTERISTICS DUE TO THE JAHN-TELLER EFFECT IN CSBR-AG- AND CSI-AG- CRYSTALS

We have investigated the polarized emission from Ag- centers in CsBr a nd CsI single crystals with CsCl structure. Azimuthal dependences of t he degree of polarization for the C emission reveal that the relaxed l attice configuration of the T-1(1u) state in both crystals has tetrago nal symmetry due to the static Jahn-Teller effect. The degree of polar ization decreases with increasing excitation energy and temperature. T hese behaviours can be qualitatively explained by the adiabatic potent ial energy surface of the T-1(1u) excited electronic state in the two- dimensional E-g configuration coordinate subspace.